Study on Rheological Properties of Waste Cooking Oil and Organic Montmorillonite Composite Recycled Asphalt

Pre-treated waste cooking oil (WCO) and organic montmorillonite (OMMT) were employed for the recycling of aged asphalt, which resulted in the improvement of the design of WCO asphalt rejuvenators and the enhancement of high-temperature performance of WCO-recycled asphalt. The effect of the rejuvenator and the properties of recycled asphalt were evaluated by viscosity, dynamic shear rheometer (DSR), bending beam rheometer (BBR) and scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC) tests. The results indicated that aged asphalt could be obviously softened and restored to the level of original asphalt by adding 6% WCO. However, the high-temperature properties of recycled asphalt would be declined by adding too large a dose of WCO rejuvenator. The high-temperature performance of recycled asphalt was significantly improved by the WCO-OMMT complex rejuvenator, and the viscosity and rutting factor of recycled asphalt were increased. Light components of aged asphalt could be supplemented by WCO of the complex rejuvenator. The volatilization of small molecules could be slowed down by the peel structure formed by OMMT and small molecules of the asphalt, which resulted in the proportion of small molecular substances (SMS) being increased by 4% and improvement of the colloidal structure of aged asphalt. The high-temperature and low-temperature performance of recycled asphalt can be improved concurrently by the combination of 6% WCO and 1% OMMT, and this was evidenced by the fact that the high-temperature and low-temperature PG were all upgraded by one level.